This invention relates to brake lathes for resurfacing automotive disc brakes, and more particularly, to a portable brake lathe which is mountable on a brake caliper mounting bracket of an automobile to resurface disc brakes adjacent thereto without removal of the discs from their mounted position on an automobile.
The first brake lathes utilized to resurface automotive brake discs for use with caliper or spot-type brakes were conversions of lathes originally meant for resurfacing the inner cylindrical surfaces of brake drums. Brake lathes originally designed to resurface the inside of brake drums were independent self standing lathes having a rotatable hub on which a brake drum could be mounted, and a tool support mounting for a single boring bar which was fed parallel to the axis of the hub but spaced therefrom a distance equal to the radial distance between the hub axis and the cylindrical drum contact surface. The addition of a tool support assembly for simultaneously removing metal from both sides of a brake disc mounted on the hub is shown in U.S. Pat. No. 3,626,793. The tool feed for an automobile brake disc resurfacer is perpendicular to the tool feed utilized for a brake drum resurfacer.
Typically, use of independent standing automotive brake lathes required removal of the brake disc from the wheel hub assembly so that the disc could be mounted on the brake lathe hub assembly. Removal of brake wheel discs requires the removal of the wheel and tire, and removal of the brake or spot caliper unit from its position surrounding a segment of the brake disc. This is accomplished by disconnecting the caliper unit from its mounting bracket which is a part of the wheel hub assembly and is positioned behind or inwardly of the removable brake disc on the hub assembly. Typically, brake caliper mounting brackets include a pair of distal arms extending from the wheel hub in a somewhat crescent shape and have apertures adjacent the distal ends thereof for mounting the brake caliper unit thereon. While some rotors or discs are fixed to the hub by bolts or the like, some rotors are mounted loosely on the hub over the wheel lug nuts so that tightening the wheel onto the hub retains the rotor in mounted position.
In order to avoid much of the work necessary to remove each wheel brake disc from the automobile in order to mount same to the independent standing brake lathe, small portable cutting tool support assemblies have been developed which mount to the brake caliper mounting bracket by means of adjustable and swingable links, or by means of a fixed non-adjustable mounting member, with both such mechanisms being shown in U.S. Pat. No. 4,388,846. The fixed non-adjustable mounting bracket tightly secures the tool support fixture to the brake caliper mounting bracket on the automobile for which the unit is designed to fit. However, with automobiles from around the world presently utilizing many varying brake systems, adjustable mounting systems are required to service automobiles having differing brake caliper mounting brackets. The use of swingable links for adjustably mounting the tool support fixture assembly onto a brake caliper mounting bracket provides the necessary adjustability for mounting the unit on differing brake caliper brackets, but the use of links which flop around when not properly tightened may allow the tool support assembly to be mounted on the brake calipers support bracket in a position other than optimum for the resurfacing procedure.
A need has developed to provide an improved assembly for mounting a dual brake disc resurfacing tool to the brake caliper mounting bracket on the hub of an automobile wheel. Such an assembly should provide adjustability of the mounting mechanism, while assuring balance and positive optimum mounting of the fixture on the brake caliper support brackets.
It is therefore an object of the invention, generally stated, to provide an improved mechanism for positively and adjustably mounting a dual brake disc resurfacing tool to the brake caliper mounting bracket of an automobile wheel hub assembly.